nelson



Feb. 1- 1927.

M. L. NELSON MULTI 7 OFF'I CE TELEPHONE SYSTEM original Filed A112. 171921 1 7 Sheets-$hee 1 (lilo VNN M. L.' NELSON dr 0M rt. n[ V in. w E wwV 'Feb. 1 1927.

MULTI-OFFICE TELEPHONE SYSTEM Original Filed Aug. 17, 1921 Feb. 1 M. L.NELSON MULTI-OFFICE TELEPHONE SYSTEM '7 Sheets-Sheet 3 Original FiledAug. 17. 1921 InLrE nImP M mu LNefsmn Feb. 1, 1927.

1 Y 7 1,615,998 M. L. NELSON MULTI OFFICE TELEPHONE SYSTEM OriginalFiled na 1921 v Sheets-Sheet 4 ]mre D151 WHEEL-.NEZEUU Feb. 1 1927.1,615,9Q8

M. L. NELSON MULTI-OFFIQE TELEPHONE SYSTEM Original Fi led Aug. 1'7.1921 '7 s s 5 Z M5PIZFLL-NEZ5UZ7 Feb. 1, 1 27. I 1,615,998

M. L. NELSON MULTI 0FFICE TELEPHONE SYSTEM Original Filed Aug. 17. 19217 s e t --5 7 Nbrfm LNEZEU n Patented Feb. 1, 1927.

UNITED STATES PATENT orrice.

MARTIN L. NELSON, OF PARK RIDGE, ILLIITOIS, ASSIGNQE, BY ME$NEASSIGNMENTS,

'IO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CURYORATION OFDELA- WARE.

MULTIOFFICE TELEPHONE SYSTEM.

Application filed August 17, 1921, Serial No. 492,976. Renewed April 20,1926.

The present invention relates to multio'l'llce telephone systems, moreespecially to such systems as comprise both manual and automaticoilices, or exchanges; and the objcct of the invention, broadly stated,is the provision of new and improved arrangements for handling thosecalls which originate at a manual ofiice and which are completed in anautomatic office.

More particularly, the present invention is in the nature of animprovement over copending application Serial Number 443,688, tiledFebruary 9, 1.921. The particular object of the invention is to providemeans whereby the time required for the B operator in the automaticexchange to set up a connection is minimized. This is accomplished by soarranging the circuits at the B operators position that instead ofhaving to wait for the A. operator to seize the assigned trunk line theB operator only registers the desired number. Now as soon as the Aoperator seizes the designated trunk line the sending operations areautomatically initiated.

A clearer understanding of this improvement may be obtained byconsidering the arrangement in the prior system which is in generalsimilar to the present one. In this case a B operators sending equipmentis located at the automatic exchange. This apparatus includes a sendingswitch, and a plurality of relay storage devices, together with circuitswhereby the digits, correspond ing to successively actuated digit keys,are registered on the storage devices, whereby the storage devicessuccessively control the sending switch according to the registereddigits, and whereby the apparatus is auto matically disassociated fromthe trunk line in use when the connection is completed.

In this prior system the operation is briefly as follows: The A operatorat the manual exchange. upon ascertaining the desired called subscribersnumber, actuates the key of her order wire extending to the properautomatic exchange and gives this number to the B operator therea't. TheB operator. upon receiving this number, immediately registers it bymeans of push buttons provided for the purpose. and assigns an idletrunk line to the A operator. When the A operator extends the connectionover this trunk line the B operator operates the start ing keyassociated with the sending equipment in. use whereby the sendingapparatus starts functioning and the connection is automatically set up,the B operator having to pay no further attention to the connection.Immediately upon the completion of the sending operation the sendingequipment is disassociated from the connection and may be used. again.However, in the case above referred to, it is necessary that the Boperator wait until the A operator extends the connection to thedesignated trunk line before operating her starting key. This is, ofcourse, undesirable as it slows up the work of the B operatorconsiderably. The present invention, as before mentioned provides meanswhereby as soon as the A operator seizes the designated trunk linesrelay is energized which automatically starts the sending operation;thus eliminating the necessity of having the B operator actuate a keyafter the trunk line has been seized by the A operator. Immediately uponbeing started the sending operation proceeds as outlined above. Thisautomatic starting arrangement enables the B operator to work a greatdeal faster as she does not have to devote as much time to eachindividual connection as was the case in the former system.

The above and other objects of the invention will be described in detailhereinafter reference being had to the accompanying drawings.

For an understanding of the circuits, Figs. 1, 2, 3, and 4 of thedrawings should be laid out in order with corresponding lines at theends thereof in alignment. while Figs. 5, 6. and 7 should be similarlylaid out im mediately below Figs. 2, 3, and 4:, respcctively. Thedrawings when thus arranged show an inter-office trunk line connecting amanual exchange with an automatic exchange, and the associated equipmentrequired to establish a connection between two subscribers lines such,for example, as the line of the manual substation A, Fig. 1, and theline of the automatic substation A. Fig. 4. The connection, whenestablished, involves a manual cord circuit such as the cord circuit 0.Fig. 1; an inter-ofiice trunk line, manual to automatic, and associatedtrunk equipment, shown in Fig. 2; a first selector switch D, Fig. 3; asecond selector switch such as the second selector 1]; and a finalconnector switch such as the connector H, Fig. l. The apparatus shown inFigs. 5, 6, and 7 constitutes a B operators sender which is used tocontrol the setting 01": the automatic switches, and which may bete1nporarily associated with the trunk line for this purpose.

The equipment shown in Fig. 1 comprising the telephone station A and theassociated line equipment at he exchange, the operators cord circuit 0,and the A operators head set, is all manual equipn'ient ot well knowntype and on this account will not have to he described.

The inter-otlice trunk line, comprising conductors 30 and 81, is one ofa large groiu') 01" similar trunk lines and extends from the jack J inthe outgoing trunk multiple at the A board, in the manual exchange, byway of the B operatofls position, shown in Fig. 2, to the first selector1), which is shown in Fig. 3. At the li opcratims position the trunkline is normally open and is provided with a group of relays, whose circuits are shown in full, and whose opera tion will also he described inthe course of the general explanation. According to the usual practicethere is a. call circuit, or order wire circuit, which terminates in theB operators head set at the automatic exchange, and which is multipledin the call circuit keys at the A board in the manual exchange.

The first and second selectors D and E are automatic switches of thewell known Strowger vertical and rotary type, such as are in common usein numerous autoi'natic telephone exchanges throughout the country. Theconnector His likewise a Strowger vertical and rotary switch and issimilar in mechanical construction to the selector switches D and E. Thecircuits are arranged, however, for a directive control in both thevertical and rotary movements. switches are operated according to thewell known two wire system of control. The connector switch H has accessto 100 subscrihers lines, one of which is the line extending toautomatic sub-station A. The reference character C'indicates a rotaryline switch of well known type which is individual to the line ofsubstation A, and which is used by the subscriber thereat for makingoutgoing calls.

The l) operators sender showni herein comprises a set of digit keys,shown in the lower left-hand corner of Fig. 2, a sending switchindicated by the reference character S, and including a plurality ofassociated relays, all of which are shown in 5, a first digit storagedevice, shown in 6, a second digit storage device, shown in 7, and thirdand fourth digit storage de vices, which are not shown but are in alltherewith.

All o't these respects exactly like the second digit storage devicewhich is shown in Fig". 7. There is also a lamp indicating device, shownin Fig. 8 on the same sheet with Fig.

The digit keys, Nos. 1 to O, inclu are ordinary self restoring keys.push buttons, located in a single row in front of the lloperator andcontrol the setting of the storage devices. There is also a release keyand a lamp L located in the same row with the digit keys. The sending)switch iii, in Fig. 5, is a simple rotary switch havii'ig two horizontalrows ot hank contacts and the two wipers 207 a d 208 associated Thesewipers are adapted to be driven by any suitable form ol? ratchetmechanism in a forward direction only by means of the stepping magnet20?. The cam 298 is mounted on a constantly rotatin; shaft which isdriven by a small motor, or other suitable means, at a speed ot-aboutten revolutions per second. This is the impulse sending cam and may hecommon to a number of ditlierent senders.

The first digit rm. (3, comprises storage device, shown in lhe digitrelays 27l270, inclusive, and the five relays 2504254, inclusive. Theother storage devices are very similar to the first digit storage dcvicand all of them will he described in full hereinafter.

A little f rther description of the apparatus at the B operatorsposition may now be advisable before proceeding; with the operation ofthe system. In addition to the intercfifice trunk line, shown in Fig. 2,there may he perha is fifty or more other trunk lines, all extendingthrough the position by way of their respective associated relayequipn'ients to firstselector switches. In addition to the operatorssender which is shown in. the drawings, there are two r three othersenders, makin perhaps tour altogether, and each sender terminates in atour conductor trunk line which. is multipled at the relay ccniipments'of all at the inter-cilia trunl: lines. Thus, any sender may beconnected with any inter-ofiice trunk line. The local trunk lineassociated with the sender saown in the drawings, comprises conductors221- 224, inclus=ve, which conductors are conthere is a similarindicating device for each of the other senders. This indicating devicecomprises a plurality of banks of switchboard lamps, there being a lampin each bank for each of the ten digits. The number of different banksof lamps will, of course, de-

pend upon the number of digits in the telephone numbers; for four digitnumbers four banks of lamps will, of course, be required as illustratedin the drawing. The digits to which the lamp corresponds are printed ona semi-transparent screen behind which the lan'ips are located, andthese numbers are ordinarily scarcely discernible. Vhen the lampsimmediately behind any series of digits are lighted, however, tl'resedigits will stand out clearly and may be read by the operator with greatfacility. The manner in which the lamps are connected exceedinglysimple, and on this account the wiring has not been drawn out in detail.it may be explained, however. that one side of all of the lamps isconnected to the exchange ballery while individual conductors run fromthe other side of each lamp to contact springs on the digit relays otthe several storage devices. Thus, the individual conductors, suchconductor 284, which come from the ten lamps in the first digit bank areconnected to springs of relays 271-270, inclusive; the conductors suchas conductor 335, coming from the lamps of the second digit bank areconnected to contacts of relays 321-820, inclusive, of the second digitstorage device, while the conductors coming from the lamps in the thirdand fourth digit banks are similarly connected to the contacts of thedigit relays in the third and fourth storage devices, respectively.

The operation of the system in establishing a telephone connection willnow be explained, it being asumed for this purpose that the subscriberat substation A in the manual exchange desires to obtain connectionwiththe subscriber at substation A in the automatic exchange. Thetelephone number at substation A will be assumed as No. 4567. When thereceiver is removed at SllbE-it-fttlOll A, a circuit is completed overthe line conductors 2 and 3 for the line relay 4, which is accordinglyenergized and lights the line lamp L. This notifies the A operator, atwhose position the answering jack J appears, that a call has beenreceived and she will respond by inserting the answering plug oi. anidle cord circuit, the cord circuit or example, in the jack J. Upon theinsertion of the plug, a circuit is completed over the sleeve conductorthereof which includes thecut off relay 5 of the calling line, and thesupervisory lamp L in the cord circuit in series. The cut oil relay 5 isaccordingly energized and disconnects the line relay l. The supervisorylamp L would. be lighted at the same time were it not for the tact. thatthe receiver isoit at substation A, whose transmitter is now suppliedwith current from the cord circuit. As a result, the supervisory relay 8in the ring side of the cord circuit is energizedand shunts out the lampL to prevent it from being lighted.

The A operator will now throw her key K to listening position in orderto obtain from the calling subscriber the number of the party with whomhe desires to converse. Having ascertained that the desired number isthe No. 4567 in the automatic ofhce, the operator will restore herlistening key and will depress the proper all circuit button in order toconnect her head set with the call circuit extending to the desiredoliice, or exchange. The call circuit button at this particular Aoperatofls position, which is associated with the particular automaticexchange in question, is the button P, and when this is depressed the Aoperators head. set is connected directly with the B operators head setin the automatic otiice. The A operator now repeats the No. 4567 to theB operator; and this number is registered by the latter operator bymeans of the di git keys associated with one of her senders as soon asit is received, it being understood, of course, that in the present casethe sender which is shown in the drawing is the one which will be used.In registering the number, the B operator will depress the digit keys l,5, 6, 7, and the starting key K in rapid succession and the entirenumber is completely registered and the sending apparatus prepared foroperation practically as soon as the A operator has finishedtransmitting the number. The key K is associ ated with the trunk line inuse and also with the sender upon which the desired nui'nber has beenregistered in order to connect this sender with the trunk line. As soonthe A operator is through talking the B operator will reply with thenumber of an idle interotfice trunk line. The A operator now inserts thecalling plug of the cord circuit in use in the designated j acl: in theoutgoing trunk multiple. Assuming that the trunk line comprisingconductors and 31 is the trunk line assigned, the plug will be insertedin the jack J and a circuit is immediately completed over the two sidesot the trunk line in series for the bridged relay so at the B operatorsposition. Relay &0 is energized by current flowing from the cord circuitat the A board and closes a circuit for the busy lamp L. This signalnotifies the B operator that the A operator has taken the trunk. Thesending switch S, Fig. 5, is now operated under the control of theseveral storage devices in succession and tour series of impulses aretransmitted over the trunk line, comprising conductors and 61,connecting Figs. 33 and 3, whereby the first selector D, a secondselector, such as the selector F and a connector, such as the connectorH, are operated in order to complete connection to the desiredsubscribers line. The B operator, having actuated the various digit keysand the starting or trunk key K, has done all. that is required of hertoward the establishment of the connection and need pay no furtherattention to it. The sender, upon which the number has been registered,controls the automatic switch-es without any further attention, and whenthe last switch has been operated the sender is automaticallydisassociated from the trunk line and is ready for use in registeringanother called number.

e will return new to the point where the B operator begins to registerthe number transmitted to her by the A operator in order to go into thesubsequem circuit operations more in detail. The ten digit relays of thefirst digit storage device are normally connected to the ten leads, orcon ductors, coming from the ten digit keys, and when theoperatordepresses the No. l digit key a circuit is completed overconductor- 23% for the fourth digit relay Upon energizing, relay 2%prepares a locking circuit for itself at armature 281; connects thegrounded conductor 228 to conductor 28% which extends to the No. 4 lampin the first digit bank of the lamp indicating device, and causes thedigit 4 to be immediately displayed; and connects the grounded conductor288 with the conductor 2% which extends to the lower bank of the impulsesending switch S and there terminates in bank contact 294. The operatordepresses the digit key only for an instant and when it is released,relay 274; is held up over a locking circuit which includes relay 252and the grounded conductor 226. Relay 252 is.

accordingly energized in series with'relay 274 and at its armature 258closes a circuit for relays 253 and 254 in series, which, uponenergizing, disconnect all of the digit relays 271-270, inclusive, fromthe conductors coming from the digit keys. Relay 274, of course, remainsenergized over its locking circuit. Relay 252 also connects ground to heholding conductor 223 at armature 260, and at armature 259 connectsground to conductor 285 extending to the second digit storage deviceFig. 7, thus completing a circuit for relays 30 i and 305 in series.Upon energizing, these relays connect the ten digit relays 321 to 320,inclusive, to the ten conductors coming from the digit keys. In thismanner the second digitstorage device is prepared for registering thesecond digit.

It will be clear now that when the No. 5 digit key is depressed, acircuit will be closed over conductor 235 for the fifth digit relay 325of the second digit storage device.

Uponenergizing relay 325 prepares a locking-circuit for itself at itsarmature 331, connects the grounded conductor 228 to the lamp conductor335 at armature thereby displaying the No. 5 digit in the second digitbank of the lamp indicating device, and connects conductor 388 toconductor 265 atarmature 332. The latter conductor extends to the lowerbank of the sending switch 5 and terminates there in bank contact 295.lVhen the No. 5 digit key is released, ground is removed from conductor235 and relay 325 becomes locked in series with relay over conductor2S5. Relay 303 is accordingly energized in series with rel 325 and atits armature'3l2 breaks the circuit of relays 30% and 305, whereuponthese relays fall back and disconnect the digit relays 321-320,inclusive, from the conductors coming from the digit keys. Relay 303also grounds the holding conductor 223 at its armr-ture 3i 1, and at itsa 'mature'310 rrounds the conductor 385 which extends to the third digitstorage device, thereby J t" 1g a circuit for the relays, correspondi gto relays 30 land 305, which connect the ten digit relays of the thirddigit storage device with the conductors coming from the digit keys.

When the operatordepresses the No, 6 digit key, a circuit is completedover condnctor 236 for the sixth digit relay in the third digit storagedevice and this relay is energized with a result similar to thatdescribed in the case of the two previously energized digit relays, andit follows that the digit 6 is displayed in the third digit bank of thelamp incicating device, and a circuit is prepared for groundingconductor 266 which extends to the lower bank of the sending switch Sand terminates there in bank contact 296. When the operator releases theN0. 6 digit key,the sixth digit relay in the thirc digit storage devicehecomes locked in series with the associated relay, correspondingtorelay 303 of the second digit storage device, and this relay, uponenergizing, breaks the circuit of the relays through the medium of whichthe digit relays were connected to the conductors coming from the digitkeys, whereby these digit relays are again disconnected. Ground is alsoplaced upon the holding conductor 223 in the third digit storage deviceand a thesaine time ground is placed upon the conductor, correspondingto con ductor 385, which extends to the fourth digit storage device.whereupon a circuit is completed for a pair of relays in said device,corresponding to the relays 304I and 305 of the second digit storagedevice, these relays havingthe function of connecting up the ten digitrelays of the fourth digit storage device to the conductors coming fromthe digit keys.

VJ hen the No. 7 digit-key is depressed, the

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operations which take place at the. fourth digit storage deviceare'similar to those describes in the case of the other storage devices.The No. 7 digit relay is en rgized over conductor 23?, and this relaycauses the digit 7 to be displayed at the fourth digit bank of the lampindicating device and also prepares a circuit for grounding conductor2G7,which conductor terminates in bank contact 297 of the sending switchS. After the No. 7 digit key is released, the energized digit relaybecomes locked in series with a relay, corresponding to relay 303, whichis energized in order to ground the holding conductor 223 and also tobreak the circuit ot the relays which have previously been effective toconnect the ten digit relays of he fourth digit storage device with theconductors coming from the digit keys.

From the foregoin it will be understood that the tourtlnhtth, sixth andseventh digit relays in toe lirst, second, tiird, and fourth storagedevices, respectively, are new locked up, with the result that thetelephone nuni ber 4567 has been displayed on the lamp in dicatingdevice, and with the further result that bank contact 29a of the sendingswitch S has been grounded, while bank contacts 295, 296 and 297 havebeen connected with in the last three storage devices, respectivelwherein circuits have been prepared for grounding these bank contactsalso at the proper time. It should be remembered also that the holding Iconductor 223 has been grounded at each oi? the tour storage devices.The pilot amp L", which is located in line with the digit-keys of thesender, uponwhich the nun'iber has justbeen registered, is also lightedinasmuch as it is connected with the grounded holding conduct-or 223.hen the hey it opu'ated by the B operator, which takes place immediatelyalter the operation of the various digit keys, the relay is energizedover a circuit extending from ground on the holding conductor 223,springs of key K, and through the windingof relay 4-5 to battery. Relay45, upon energizing, at armature 5-il locks itself to grounded conductor223, at armature 53 prepares the circuit of the relay id, at armature 52prepares the circuit of relay 44;, and at armature 51 lights the callinglamp L The function of the lamp indicating device, upon which the digitsare displayed as fast as they are registered. is to indicate completedtelephone nun'ibers to the B operator with a View to affording her acheck on the accuracy of her work. In order to obtain the best resultsand the maximum speed of operation is intended that the B operator willregister the di 'its in the telephone numbers as they are transmitted toher by the A operator. from which it will be evidentthat the digit keysare necessarily operated with rest rapidity, and in quick succession.rilthough an experienced operator soon becomes accustomed to this andWlll make very few mistakes, there will be times nevertheless when sheis interrupted in her work or for some other reason is uncertain whethershe has re 'istered the correct number or not, and at such times thelamp indicating device affords a convenient method of at onceascertaining what number has actually been registered. If it is notdesired to use the indi cating device constantly, a key may be insertedin the battery conductor inorder to disconnect the current supply fromthe lamp, and the key may then be operated whenever it is desired toshow up some particular number. In case an inspection of the indicatingdevice should show that a telephone number has been registeredinaccurately, the release key It may be actuated in order to energizerelay 203 for the purpose of re storing the digit relays of theseveralstorage devices to normal position. The manner in which this isaccomplished by the operation. of relay 203 will be clear from thesubsequent explanation of the restoration of these relays under ordinarycircumstances, consequently it will not be necessary to make an;detailed explanation of it at this time.

Having completed the registration of the number, the B operator assignsa trunk to the A operator, as previously explained and need pay nofurther attention to the call. As soon as the A operator takes thetrunk,

the B operator is notified of the fact by the lighting of the busy lampL Another result of the energization of the bridged relay 4:0 is that acircuit is completed in multiple with that of the lamp L for the upperwinding of relay 4:6 by way of grounded conductor 62. Upon energizing,relay l6 locks itself to the grounded holding conouctor 223 at itsarmature 57, closes a circuit for the upper winding of relay a l atarmature 56, and at armatures 55 and 59 connects the trunk conductors 60and 61 with the conductors 221. and 222 coming from the send-. ingswitchS, Fig. 5. Conductors 221 and 222 are normally connected together atari'nature 212 and also at armature 214 of relays 201 and 202 of thesending switch S, and it follows, therefore, that a circuit is completedover the trunk conductors 60 and 61 for the line relay 65 of the firstselector D, Fig. 3. Upon energizing, relay 65 closes a circuit for theslow acting release relay (36. The latter relay, upon energizing, opensa point in the circuit of the release magnet 72 and prepares a circuitfor the vertical magnet in the customary manner.

Relay 4% is operated when the circuit is closed through its upperwinding and completes a locking circuit for itself at its armature 61.In addition relay a l closes a pair of contacts in the trunk conductorsin order that when the relay 46 deenergizes, as will occur shortly, thesaid trunk line may extend continuously through the operators position.lVhen relay 16 is energized, as just explained, the conductor 224 isgrounded, being connected with conductor 223 atarma turc 58, and acircuit is completed for slow acting relay 20%, Fig 5, Uponenergizing,relay 20 1 closes a circuit for slow acting relay 205 at its armature217 and its armature 21 disconnects ground from the conductor 2 8. Thelatter. operation extinguishes the lights. in the lamp indicatingdevice, and when the slow acting relay 205 pulls up it'opens the normalground connection toconductor 22 6 at itsafmature 219 and substitutestherefor aground coming from the working contactcf armature218 of re?lay 204. Since relay 2041-is already ener gized and since thecontactsatarmature 219 are of the, makebefore break type, con.- ductor 226 isheld grounded continuously during this operation. In addition to causingthe operation of relays 204 and 205, the.

grounding of conductor 22 1 produces another result, which is theclosure of a cireuitfor the impulsingrelay 202. This circuit is brokenatthe rate of about ten times per second by the constantly. rotating cam298, and the circuit is accordingly closed the first time the said camcomes into the proper position after the conductor 22% is grounded.Relay 202 is now intermittently energized and deenergized by theoperation of cam 298. 202 does not open the circuit ofthe line relayofthe first selector D atarmature 2llbecause this circuit is closedalsoat armature 212 ofrelay 201. At armature 215, however, a circuit iscompleted forthe.

stepping magnet 206 ofthe sending switch S and this magnetis energized.Upon the deenergization of relay 202 the circuit of the stepping magnet206 is broken and the said magnet retracts its armature, therebyadvancing the wipers 207 and 208 one step. The wiper 207 now engagesgrounded contact in its associated bankand thereby closes a circuit forthe slow acting relay 201 which ener izes and Jrepares a locking.circuit for slow acting relay 200. Relay 201 also opens, at armature212, the shunt circuitwhich normally renders theiinpulsingrelay 202ineffective to interrupt the circuit-of the line relay of the selectorD. The; impulsing relay 202 continues to be energized and deenergizedintermittently by the operation of the cam .298, and at eachenergization this relay will separate the two conductors 221 and.222 andwill thereby produce a series of interruptions in the cir cuit of theline relay 65 of the selector D. At the same time relay 202 transmitsaseries ofimpulses to the stepping magnet 206 at armature 215, andthesending switch S is thus driven synchronously with the first At thefirst energization relaythe firstselector.- After four interrupt-ionshave been produced in this way, the stepping magnet 206 will have beenenergized four more times, and the wiper 208 will be advanced intoengagement with the now grounded bank contact 294. A- circuit is thuscompleted for theslow acting relay 200,-which immediately energizes,establishes a locking circuit for itself atits armature.

210, and at its armature 211 opens the. circuit of the iinpulsing relay202, thus pre venting the transmission ofwany more impulses over thetrunk circuit for thetime being. Relay 200 also closes a new circuit forthestepping magnet 206 at armature. 209-, and sincethis circuitincludesan inter rupter contact controlled .by the stepping;

magnetitself, the said stepping magnetwill operate in the manner of abuzzer and the.

switch will be advanced automatically until wiper 207 arrives at thefirst ungrounded' contact in its bank which, as shown in the drawing, isthe twelfth bank contact. Duz ing this time certain operations aretaking place at the. first digit storage device whichwill now be.explained.

At the same time that a circuit is completed for relay 200 by thearrival ofwiper 208 at grounded bank contact 294, a circuit is completedby this wiper which extends over. conductor 227 and by way of armature255 and its; resting contactto relay 251 at the first digit storagedevice, thus energizing this relay. As explained before the switch Scontinues to advance its wipers and as soon as another step is. taken,wiper 208 will" the energization of relay 250 are the opening of theground connection at armature 257 to the holding conductor 223 in thefirstdig t storage, device (it will be recollected that this holdingconductor is still grounded in each of the other three storage devices);the removal of ground from conductor 288, at armature 256, wherebyground is disconnected from bank; contact 29% in the bank of the.sending. switch S; andthe grounding.

conductor 286 at the same armature 256, whereby ground is extended byway of the energized digit relay 325 of the second digit storage device,and conductor 265 to bank contact 295 of the sending switch S. Theoperations so far described have resulted in the transmission of aseries of-four impulses to the selector D, 'or more specifi callyspeaking, the circuit of the line relay of the said selector has beeninterrupted four times and in response to these interruptions theselector is operated to raise its wipers to the fourth level, and at theend of the series of impulses it operates automatically to select anidle trunk leading to a second selector, such as the second selector E.tleturning again to the operation of the sending switch, when the wiper207 arrives at the twelfth contact in its associated bank, which isungrounded, the circuit of the slow acting relay 201 is broken and afteran instant this relay will fall back, thus opening the locking circuitof slow acting relay 200 and at the same time closing the normal shuntcircuit around the iinpulsing contact at ar iature 214 of the impulsingrelay 202. Its circuit having been broken, the slow acting relay 200also deenergizes after a brief instant and at its armature 211 againcloses the circuit of the iinpulsing relay 202. Thus relay now beginsoperating as before and on its first energization transmits an in'ipulseof current to the stepping magnet 206 with out, however interrupting theswitch control circuit over the-trunk line, which now extends through tothe second selector E. On the first step of the sending switch S, wiper207 arrives at the thirteenth bank contact and since this contact isgrounded a circuit is completed for the slow acting relay 201. whichoperates to open the shunt circuit at its armature 212 as before.Subsequent energiZat-ions ot' the iuipulsing relay 202 now cause thecontrol circuit extending to the selector E to be interrupted aplurality oi times, while at the same time the stepping magnet 206 isintermittently energized to drive the wipers oi the sending switch. Whenwiper 208 arrives at the eighteenth contact in its associated bank,which contact it connected in multiple with the bank contact 295, acircuit will be completed for relay 200, and this relay is energized asbefore to open the circuit of theinipulsing relay 202 and thus stop thefurther transmission of impulses. Relay 200 also close the usual circuitfor continuing the operation of the stepping magnet 206 and the sendingswitch is, therefore, continued in motion untilthe wiper 207, arrives atthe next ungroundcd bank contact, which is the twenty-fifth. At the sametime that rela 200 is energized, a circuit is completed by way ofconductors 227 and 287 for relay 302 in the second digit storage deviceand the said relay 302 is energized. As the sending switch continues itsadvance, this circuit is broken and relay 302 becomes locked in serieswith relay 301 to the, grounded conductor 285. Relay 301 is accordinglyenergized and at its armature 306 disconnects conductor 28'? from thewinding of relay 302 65 and transii'ers it byway of conductor 28? to asimilar relay in the third digit storage device. In addition, relay 301disconnects the grounded conductor 286 from conductor 388, therebyremoving ground from the bank contact 295 in the bank or" the sendng iswitch S, and transfers it into connection with conductor 886, wherebyground is extended by way of the new energised sixth digit relay in thethird digit storage device, to bank contact 296 in the bank of thesending switch, and at armature 308 of relay 301 the ground connectionto the holding conductor 223 in the second digit storage device isbroken.

The second series of operations at the operators sending equipmentresulted in the transmission of five impulses to the selector lfl, orrather in the production oi? live ruptions in the circuit of itslinerelay 90, whereby the switch shaft and wipers are raised oppositethe fifth level of bank contacts. Upon the (:css tion of the series ofimpulses, the second selector it automatically operates to select anidle trunk leading to a connector switch, such as the connector ll, Fig.l.

When the wiper 207 of the sending switch arrives at the twenty-fifthbank coinact it finds this contact ungrounded, the advance or the switchis stopped temporarily, and relay 201 is dcenergized, thus againshuntin' the ii'npulsing contact at armature 214:. ter a brief: furtherinterval, the slow acti relay 200 will :lall back and again close thecircuit ot in'ipulsing relay 202, which now begins operating as before,and produces a series o'li ii'ltcrruptions in the control circuit of theconnector H to operate this switch vertically, while at the same timethe impulses are transmitted to the stepping magnet 206,, in order todrive the sending switch S. It is understood, oi? course, that the firstenergization of relay 202 is incliective to interrupt the controlcircuit. It will be unnecessary to minutely consider all the operationswhich take place during the transmission of the third and fourth seriesof impulses. The third series is terminated by the arrival of wiper 208at grounded bank contact 206 which causes relay 200 to be energized, inorder to advance the sending switch automatically to the twelfth contactin its bank, and which closes a circuit over coi'iductors 227, 287, andto the relay in the third digit storage device which corresponds torelay 382 of the second digit storage 'levice. Upon the removal ofground from conductor 227 by the further advance of the sending switch55, a relay in the third digit storage device, corresponding to relay301 of the second digit storage device, is cncrgized and varioustransfer oper ations take place which result in the removal of groundfrom bank contact 296 and in the grounding of bank contact 207.

The connector l'l responds to the third series of impulses, and itsgha'l'tand wipers are raised five steps untilthey stand oppo site thefifth level of bank contacts. No automatic movement takes place attheconnector, however, upon the cessation of the series of impulses andfurther movementof the connector is deferred until the arrival of thenext series of impulses.

When the wipers of the sending switch- S arrive at the twelfth set ofbank contacts, wiper 207 will find no ground and relays 201 and 200 areaccordingly deenergized-to again start the operation of the switch. Theimpulsing relay 202 now begins to step the switch S aroundas before, andafter the first step begins to transmit the final series of impulsesover the control circuit to the connector H. This last series ofimpulses is terminated by the arrival of wiper 208 at the twentiethcontact in its bank which is connected in multiple withbank contact 297and which is, therefore, grounded. lVhen this occurs, relay 200 isenergized as usual to stop the transmission of impulses and to close theautomatic stepping circuit for the stepping magnet 206 of the sendingswitch. At the same time conductor 227 is grounded, and a circuit iscompleted over said conductor and conductors 287 and 387 and thence byway of asiinilar conductor, in the third digit storage device, to arelay in the fourth digit storage device which corresponds to relay 302of the second digitstorage device. As the sending switch continues itsadvance ground is removed from conductor 227, whereupon a transfer relayin the fourth digit storage device, which corresponds to transfer relay301 ofthe second digit stor age device, is energized. Since the fourthdigit storage device is the last one, it will be apparent that thoseconductors, corresponding to conductors 385, 380, and 387, will beomitted, and the principal result of the operation of the transfer relayis the removal of ground from the holding con.- ductor 223. Ground hasalready been removed from this holding conduct-or at each of the otherthree storage devices, and it' follows that conductor 223 will now beentirely clear of ground. At the same time that conductor is cleared,conductor 224 is cleared of ground also for this conductor has beenmaintained grounded through its'connection with conductor 223 atarmature 58 of relay 46. The removal of ground from conductor 224permanently opens the circuit of the impulsing relay 202 and thusprevents any further operation of thesending switch S at this time. Theremoval of ground from conductor 224 also ductor 226 at armature 218. Asa result of the latter operation, relays 250, 251, 252, and 274 of thefirst digit storage device'are deenergized. Relay 252, upon. deenergizinopens the circuit of relays 253 and 254 which are thus dcenergized also,and also ren'ioves ground from conductor 285 at armature 250. By thelatter operation relays 301, 302, 303, and 325 of the second digitstorage device are. deenergized. Relay 303, upondeenen gizing, removesground from conductor 385 Xtending to the third digit storage device,and as a result the corresponding relays in this storage device aredeenergizedalso. In a similar way, the relays in the fourth digitstorage device, which have been locked up, 1

are vdeenergized an instant later. The operators sending. equipment,including the four digit storage devices and the. sending switch S, is.thus entirely restored to normal position and is ready for use again inregistering another telephone number.

At the trunk line, Fig. 2, when ground is removed from the holdingconductor 223 the locking circuit ofrelay 46 is broken and thus therelay. is accordingly deenergized. As a result the circuit ofrelay 44 isbroken, but. this relay remains locked up to the grounded. conductor 56at its armature 61. By the deenergization of relay 46, the incomingconductors 30 and 31 of the interoflice trunk line, are. connectedthrough the two condensers by way of armatures 49 and 50 of relay 44,and through the normally closed sets of contact springs controlled byrelays 46 and 48 to the outgoing trunk conductors and 61, which havebeen extended, by. the operation of selectors D and E and the connectorH, to the desired called line. It will be observed that there is abridge across the trunk conductors '60 and 61 at the B operatorsposition which includes the impedance coil 43 and upper winding of theelectropolarized relay 42. Thus, the continuity of the switch controlcircuit extending throughto the connector H ispreserved and the switchesare prevented from releasing. The two windings of relay 42 are inopposition at this time and consequently this relay is not operated. Bythe removal of ground from the holding trunk conductor 223 thelockingcireuit of the relay 45 is opened and this relay deenergizes torestorev certain circuits to. normaland to extinguish the calling-lamp LBy the effacementof this signal the B operator is notified that theconnection has been completed and the sending equ-ipmentis free.

The operation of the automatic switches will now be explained a littlemore in detail, in order that the entire system may be fully zoounderstood without reference to other publications. As previouslyexplained, the control circuit of the first selector D includes theconductors 221 and 222 coming from the sending switch S. and the trunkconductors and 61, and when the first series of interruptions isproduced in this circuit by the intermittent impulsing relay 202 of thesaid sending switch, the line relay of the first selector is caused toretract its armature a corresponding plurality of times. At eachretraction of its armature, relay 65 sends a current impulse through theslow acting series relay 67 and the vertical magnet 70 in series, andthe vertical magnet is operated to raise the switch shaft step by stepuntil the wipers 80,81, and 82 stand opposite the fourth level of bankcontacts. Relay 67 energized in series with the vertical magnet, andbeing slow acting retains its armature in operated position throughoutthe vertical movement of the switch. At the first upward step, the oilnormal springs 78 are closed and since relay 67 is in operated positiona circuit iscompleted for the stepping relay 68. Upon energizing, relay68 establishes a locking circuit for itsel'i at its upper armature, andat its lower armature prepares a circuit for the rotary magnet 71. Atthe end oi the vertical movement of the switch, the slow acting relay 67is deenergized and closes the circuit of the rotary m net 71 whichaccordingly operates to rotat; the switch shaft one step and brings theswitch wipers into engagement with the first set of bank contacts in thefourth level. At the same time the rotary magnet opens its interruptercontact and thus breaks the locking circuit of the stepping relay 68,which. accordingly deenergizes and breaks the circuit of the rotarymagnet which thereupon deenergizes also and again closes itsii'iterrupter contact. The operationnow depends upon whether the trunkline terminating in the first set of contacts is busy or idle. it thistrunk line is busy, there will be a ground potential on the test contactengaged by the test wiper 81 and the stepping relay 68 will again beenergized, resulting another closure of the rotary magnet circuit andthe advance of the switch wipers into engagement with the second set ofbank contacts, and th s operation will continue as long as the testwiper 81 continues' to engage rounded test contacts.

x.) a, Z":

hen the first idle trunk line is reached, which we will assume to be thetrunk line extending to the second selector E, the test wiper 81 willfind no ground potential on the test contact 8i and the stepping relay68 will not again be operated. Instead the switching relay 69, which hasheretofore been short circuited, is energized in series with thestepping relay (58, the latter relay remaining inoperative due tothehigh resistance of the said switching relay. Upon energizing, relay 69grounds the test wiper 81 at its armature 75 in order to make theselected trunk line busy, and at its armatures 74 and 77 disconnects thetrunk conductors 60 and 61 from the winding of the line relay andextends then by way of wipers 80 and 82, bank contacts 88 and 85,conductors 86 and 88, and armatures 94L and 96 and their restingcontacts to the upper and lower windings of the line relay 90 of thesecond selector E.

WVhen the trunk conductors are extended to the selector E, as abovedescribed, the line relay 90 is energized and closes a Circuit for theslow acting release relay 9i. Upon energizing, relay 91 prepares theselector for operation in its vertical movement in the usual manner, andalso connects ground to the release trunk conductor 87, therebyestablishing a holding circuit which extends by way of said conductor87, test contact 8 test wiper 81, armature 7 5 and its working contact,winding of the switching relay 69, interrupter contacts of the rotarymagnet 71, oli normal springs 78, and the winding of the stepping relay68 to battery.

The operations just described whereby trunk conductors 60 and 61 havebeen extended through to the second selector E have occurred in responseto the transmission of the first series of impulses by the sendingswitch S. The automatic rotary movement oilthe selector D in selectingan idle trunk line in the particular level, which was selected under thedirective control of the sender, takes place during the time intervalbetween the transmission of the first and the second series of impulses.It will be recollected that this time interval is introduced by therelays 201 and 200, of the sending switch, which are slow acting andwhich, therefore, require an appreciable length of time to fall back. Itmay be up prehended that an additional time interval is introducedbetween each two series of impulses, owing to the fact that the sendingswitch S is forced to complete its travel from one of its normalpositions to the next each time a series of impulses is transmitted.This is true to a certain extent, but the time interval thus introducedis so short as to be inappreciable. The switch S travels over its bankcontacts at a rate of about sixty per second when it is advancing itswipers I automatically.

When the next series of impulses come in over the trunk conductors 60and 61., the line relay 90 of the second selector E is deenergized aplurality of times and con trols the vertical magnet 92 to raise theshaft and wipers 102, inclusive, tothe fifth level, the second digit inthe number being the digit 5, as explained heretofore. The operation ofthe second selector E is precisely the same as that of the firstselector E, and consequently it will be unnecessary to consider it indetail. It will. be sutiicient to say that at the end of the verticalmove ment of the switch, the rotary movement is initiated automaticallyand the wipers are rotated step by step in search of an idle trunk lineleading to a connector switch. Assuming that the first idle trunk lineencountered is the one shown in the drawing and extending to theconnector H, Fig. 4:, when the test wiper 100 arrives at test contact101- it will find the said testcontact imguarded, and the selectingmovement oi the switch will be arrested. The switching relay 99 is nowenergized, and the trunk conductors S6 and 88 incoming to the selectorare disconnected from the windings ot the line relay 90 and are extendedby way of armatures 9-1 and 96 and their working contacts, wipers 100and 102, bank contacts 103 and 105, conductors 106 and 108. normallyclosed contact springs of the back bridge relay 110 to the upper andlower windings oi the double wound line relay 111 of the connector H.

On the extension 01' the control circuit to the connector H in the abovemanner, the line relay 111 is energized and completes a circuit for theslow acting release relay 112. Upon energizing, relay 112 prepares theconnector for operation in its vertical move ment in the usual way andat armature connects ground to the release trunk conductor 107. Aholding circuit is thus established which extends by way of the saidconductor 107, test contact 10 1, test wiper 101, and armature 95 andits working contact, to conductor 87 where it joins a previouslydescribed holding circuit extending back to the first selector D. Theswitch ing relay 99 at the second sel ctor E is connected to the holdingcircuit the same as was described in the case or the switching relay (5901 the first selector.

\V hen the third series of impulses. corre sponding to the digit 3, aretransmitted over the control circuit by the operators sender, the linerelay 111 oi the connector H is momentarily decnergized six times and ateach deenergization transmits an impulse of current to the verticalmagnet 11.8 over a path which. extends from ground by way oi armature12s and its resting contact, armature 126 and its working contact. or?normal springs 121 and 12 winning ot' the 510 acting series relay 113,and the winding of the vertical magnet 118 to battery By the operationof the vertical magnet the wipers 150152, inclusive are raised step bystep until they stand opposite the sixth level of bank contacts. Belay113 is energized in "series with the vertical magnet 118 and being slowacting holds up continuously during the vertical operation of theswitch. By the operation of this relay, the ver'lcal magnet circuit ispreserved intact, notwithstanding the shitting of the off normalsprings, which occurs at the first vertical step of the switch. At theend of the vertical movement, relay 113 deenergizes and transfers theoperating circuit to the rotary magnet 119.

The last series of impulses comprises seven interruptions in the controlcircuit corresponding to the final digit 7 ot the called telephonenumber. Responsive to these interruptions the line relay 111 isdeenergized seven times and now sends impulses to the rotary magnet 119over the "following circuit: from ground by way of armature 124: and itsresting contact, armature 126 and its working contact, ofi" normalsprings 121 and 122, armature 127 and its resting con tact, restingcontact of armature 132, and the said armature, armature 139 and itsrestcontact, and the winding of the rotary magnet 119 to battery. By theoperation of the rotary magnet, the wipers 1.50152, inclusive, arerotated step by step and are finally brought to rest in engagenient withthe particular set of bank contacts in which the line of substation A isterminated, these contacts being indicated in the drawings by referencecharacters 153, 154 and 155. The slow acting relay 116 is energized inparallel with the rotary magnet and remains continuously energizedduring the rotary move ment. In operated position, relay 116 connectsthe test wiper 151 to the winding of the test relay 115 by means of itsarmature 133 and at armature 135 closes an alternative point in thecircuit of the rotary magnet, to guard against the possibility of having this circuit opened by the operation ot the test relay while thetest wiper 151 is passing over grounded test contacts.

The final series of impulses has now been received. and the ionnectorwipers have been placed in connection with the terminals of the calledline. If the line is busy there will be a ground potential on the testcontact 15% and the test relay 115 willv he energized. lVhen this relayoperates it prepares a loching circuit for itself at its armature 131,which is completed when the slow acting relay 116 falls back an instantlater. opens the rotary magnet circuit at armature 1 32, and armatureconnects a lead from he busy signalling machine to the lower side t theline. By this time the relay 15 at he B operators position has beendeener inc lid

subscriber will replace his receiver thereby signalling the operator whowill pull down the connection and the automatic switches will bereleased, as will be explained subseouently.

I uppose now that the called line is idle when connection therewith isattempted. Under these circumstances there will be no ground on the testcontact 154. and the test relay 115 will not be energized. Then when theslow acting relay 116 falls back a circuit is completed for theswitching relay 117 which may be traced from the grounded conductor 107by way of armature 131 and its resting contact, the upper winding or theswitching relay 117, resting contact 01" armature 113 and the saidarmature, test wiper 151, test contact 154, winding of the cut of" orswitching relay 162 of the line switch C, and winding of the steppingmagnet 16% to battery. Relays 11'. and 162 are energised in series overthis circuit, and the latter relay is effective to clear the lineconductors 160 and 161 of their normal battery and ground connections inthe line switch. It may be explained that owing to a mechanicalinterlocking device between the armatures of the switching relay 162 andthe line relay 163, the former relay is operated only about half way atthis time, and the wipers of the line switch are not connected up.

At the connector H, when the switching relay 117 pulls up, itestablishes a locking circuit for itself at armature 138, groundsthctest wiper 151 at armature 13?, opens the rotary magnet circuit atarmature 139, and at armatures 136 and 140 connects up the two linewipers 150 and 152. the latter operation a signalling circuit is established whereby ringing current from the genorator GEN is intermittentlyprojected out over the called line to operate the bridged ringer atsubstation A, and notifv the called subscriber that he is wanted. Thereturn path for the ringing current includes the upper winding of thering cut oil relay 114, and when the called subscriber answers thisrelay is operated. Upon energizing, relay 11 1 establishes a lockingcircuit for itself at its arn'iature 129, breaks the ringing circuit atarmatures 128 and 130, and at the working contacts of these samearmatures finally completes the talkingconnection.

Current is now supplied to the transmit ter at substation A through thewindings of the double wound back bridge relay 110 which is accordinglyenergized. This relay is a reversing relay and has the well knownfunction of reversing the incoming trunk conductors 106 and 108 asregards their connections with the windings of the line relay 111. Itwill be recalled now that the circuit of the line relay 111 is completedby way of the bridge through the impedance coil 13, and the upperwinding of the elechormal in the usual manner.

tro polarized relay 412 in the trunk equipment at the B operatorsposition, the operators sender having been disconnected by this time,and the operation of the reversing relay 110, therefore, will reversethe direction of current flow in the trunk line and more particularly inthe bridge thereof which includes the upper winding of the saidelectropolarized relay 412. As a result, the two windings of this relaynow co-operate and it is able to attract its armature whereby the upperhigh resistance winding of relay 40 is shunted by means of therelatively low resistance impedance coil 41. Relay 40 remains energized,owing to the fact that its lower winding is still connected in thebridge across conductors and 31, and the result of shunting out theupper high resistance Winding of this relay is to augment the flow ofcurrent sufliciently to operate the supervisory relay 7 at the operatorscord circuit in the manual exchange. This serves to extinguish thesupervisory lamp L and notifies the operator that the called subscriberin the automatic exchange has answered his telephone. The subscribersmay now converse as desired.

When the subscribers are through talking, they will replace theirreceivers. By the replacement of the receiver at substation A, 1

the supervisory relay 8 is deenergized, and the supervisory lamp L islighted. When the subscriber at substation A replaces his receiver, theback bridge relay 110 in the connector H is deenergized and thedirection of current flow in the section of the trunk to the right ofthe condensers is reversed to normal, thereby causing theelectropolarized relay 12 to retract its armature. By this operation theupper high resistance Winding of relay l0 is again included in thecircuit of the supervisory relay 7 at the A opcrators cord circuit, andthis relay is deenergized to light the su ')ervisory lamp L By thedisconnect signals thus given the operator, she is advised that the conversation is finished and she will accordin, ly pull down theconnection. lVhen the plug is removed from the jack J, the circuit overwhich relay 40 at the B operators position has been maintainedenergized, is broken and relay 410 will accordingly Iiiall back andremove ground from conductor 56.

his extinguishes the busy lamp L and also breaks the locking circuit ofrelay -14. On deenergizing, relay opens the trunk line at armatures -19and thereby clearing the bridge across the trunk conductors and 61. As aresult, the line and release relays 111 and 112 of: the connector H arepermitted to fall back and these relays jointly close a circuit for therelease nr .gnet 120, whereby the connector H is restored to Relay 112also removes ground from the release trunk conductor 107 and thisoperation breaks the holding circuit for the switching relays (39 and 99of the selectors D and E, respectively. These relays are, therefore,deenergized and circuits are completed for release magnets 72 and 93which operate to restore their associated switches to normal position.All the apparatus is thus returned to normal and is ready for use insetting up other connections.

It will now be convenient to explain certain details of the operation ofthe sending circuits which have not been taken into account in theforegoing. Under certain conditions the A operator may not take thetrunk assigned to her by the B operator, this may be from variousreasons such the calling subscriber hanging up, and it is necessary thatthe B operator be informed of this fact so that the registeringequipmentin use will not be tied up indefinitely. It will be rememberedthat the lamp lj is lighted immediately upon the operation the key K. Ifthis lamp continues to burn. without the operation of the lamp L the Boperator will know that the trunk has not been seized and she willoperate the release key R thereby restoring the apparatus to normal in amanner similar to that already described.

It will, of course, be appreciated that the B operator does notnecessarily have to operate the key K immediately after the operation ofthe digit keys and that she may do so after the trunk has been seized bythe A operator. Under these conditions, the sending operations takeplace immediately upon the operation of the key K. However, the usualmethod of operation will be to actuate the key K immediately after theoperation of the digit keys as this procedure saves considerable or theB operators time and minimizes the attention that the operator has togive to each connection.

It will be seen from the foregoing that I have devised a simple andeflicient arrangement of circuits and apparatus for handling callsbetween manual and automatic eX- changes, introducing a variety of newfeatures which not only simplify and reduce the cost of the equipment,but add to the speed and facility with which necessary duties areperformed by the operators."

Having described my invention, what I consider to be new and desire tohate protected by Letters Patent will be pointed out in the appendedclaims.

\Vhat I claim is 1. In a telephone system, A and B operators positions,trunk lines extending from the A operators position through the Boperators position to automatic switches, other automatic switches,means for manually connecting a calling line with one of said trunklines at said A operators position,

an operators sender including a registering device at said B operatorsposition, means whereby the B operator can set up the called number onsaid registering device and prepare the sender for connection to thetrunk line in use, means independent of further attention on the part ofthe B operator and responsive to the connection of said calling linewith the selected trunk line for automatically connecting the sender tothe trunk line in use, and means controlled by said registering devicefor causing said sender to send successive series of impulses over saidtrunk line to operate a series of said switches to extend a connectionto a called line.

2. In a telephone system, A and B operators positions, trunk linescoming from the A operators position and passing through the B operatorsposition to automatic switches, other automatic switches, means formanually connecting a calling line with one or" said trunk lines at theA operators position, an operators sender at the B position comprising asending switch and a plurality of storage devices, means whereby the Boperator can register the digits in the number of the called line onsaid devices and prepare the sender for connection to the trunk line inuse, automatic means independent of further attention on the part of theB operator and responsive to the manual connection of the said callingline with the selected trunk line for connecting the sender with thesaid trunk line, means also responsive to such manual connection wherebythe sending switch is then controlled by said storage devicessuccessively to transmit series of impulses over the trunk conductors tooperate a series of said switches to connect with the called line, andmeans for automatically disconnecting the sender when the connection iscompleted.

3. In a telephone system, A and B operators positions, trunk linescoming from the A operators position and passing through the B operatorsposition to automatic switches, other automatic switches, means formanually connecting a calling line with one of said trunk lines at the Aoperators position, an operators sender at the B position comprising asending switch and a plurality of storage devices, means whereby the Boperator can register the digits in the number of the called line onsaid devices, automatic means responsive to the manual connection of thesaid calling line with the selected trunk line and to a previouslycompleted momentary operation on the part of the B operator forconnecting the sender with the said trunk line, means whereby thesending switch is then controlled by said storage devices successivelyto transmit series of impulses over the trunk conductors to operate aseries 01 said switches to connect with the called line, and

means for automatically disconnecting the sender when the connection iscompleted.

4:. In a telephone system, A and B operators positions, trunk linescoming from the A operators position and passing through the B operatorsposition to automatic switches, other automatic switches, a call circuitextending between said positions whereby the A operator can transmit adesired called number to the B operator, an operators sender at the Bposition comprising a sending switch and a plurality-of storage devices,means whereby the B operator can register the digits in the callednumber on said devices, manual means at the A operators position forconnecting a calling line with aparticular one of said trunk linesassigned by the B operator over said call circuit, automatic meansresponsive to the seizing of said trunk for connecting said sender withthe trunk line assigned independent of any contemporaneous or subsequentoperation on the part of the B oper ator, and means also responsive tothe seizure of said trunk for then automatically operating said sendingswitch under the control 01" said storage devices to transmit aplurality of series of impulses over the trunk conductors to operate aseries of said switches to complete the connection to the called line.

5. In a telephone system, A and B operators positions, trunk linescoming from the A operators position and passing through the B operatorsposition to automatic switches, other automatic switches, a call circuitextending between said positions whereby the A operator can transmit adesired called number to the B operator, an operators sender at the Bposition compri ing a sending switch and a plurality of storage devices,means whereby the B operator can register the digits in the callednumber on said devices, manual means at the A operators position forconnecting a calling line with a particular one of said trunk linesassigned by the B operator over said call circuit, automatic meansresponsive to the seizing of said trunk line and to a previouslycompleted operation of relatively short duration on the part of the Boperator for connecting said sender with the trunk line assigned, andmeans for then automatically operating said sending switch under thecontrol of said storage devices to transmit a plurality of series ofimpulses over the trunk conductors to operate a series of said switchesto complete the connection ators sender at the B position comprising asending switch and 'a plurality of storage devices, means whereby the Boperator can register the digits in the number of the called line onsaid devices, a relay for connecting the sender with the trunk in use,second relay, a circuit for said first relay controlled by said secondrelay, a third reiay controlling an open pointin said circuit and meansfor energizing the said third relay responsive to a momentary operationon the part of the B operator, means for energizing said second relaywhen said calling line is connected to said'trunk line whereby thesender is connected to the trunk also, and means then automaticallyresponsive whereby the sending switch is controlled by said storagedevices to successively transmit series of impulses over the trunkconductors to operate a series of said switches to connect with a calledline.

7. In a telephone system, A and B operators positions, trunk linesextending from the A operators position through the B operators positionto automatic switches, other automatic switches, means for manuallyconnecting a calling line with one of said trunk lines at said Aoperators position, an operators sender including a registering deviceat said B operators position, means whereby the B operator can set upthe called number on said registering device and prepare the sender foroperation by performing an act of relatively short duration, meansresponsive to the subsequent connection of the calling line with theselected trunk line for initiating the operation of said sender, andmeans for automatically continuing the operation of said sender undercontrol of said registering device to send successive series of impulsesover said trunk line to operate a series of said switches to extend aconnection to a called line.

8. In a telephone system, a first and a second manual switchboard, aline extending from the first switchboard and passing through the secondswitchboard, a sending device at the second switchboard means "fortransmitting a telephone number to the operator at the secondswitchboard, means under the control of said operator for adjusting saiddevice in accordance with said number and for p-eparing to start thesender to retransmit the registered number over said trunk line, meansat the first switchboard tor subsequently completing a connect-ion tothe line thereat, and means for starting said device responsive jointlyto the said completion of the connection at the first switchboard and tosaid preparation and without further attention from the operator at thesecond switchboard.

9. In a telephone system, a first and a second manual switchboard, aline extending from the first switchboard and passing Ill)

